Method and apparatus for full spectrum polarization imaging

Abstract

Methods and systems that combine full spectrum and polarization imaging are described. An example full-spectrum imaging and polarization system includes one or more pixeled sensors with responsiveness to a wide spectral range of illumination in a range of at least 250 nm to 1.1 microns. The system further includes one or more imaging elements and one or more polarization elements that are positioned to receive illumination from an object of interest and to direct the illumination to the one or more pixelated sensors. The polarization elements are positioned to receive the illumination corresponding to the object of interest and to allow the illumination with two or more distinct polarizations to reach the pixelated detectors. A processor receives information corresponding to an intensity and polarization of illumination received from the object, and determines imaging and polarization characteristics of the object based on the received information.

Description

METHOD AND APPARATUS FOR FULL SPECTRUM POLARIZATION IMAGING CROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] This application claims priority to the provisional application with serial number 63 / 566,825 titled “METHOD AND APPARATUS FOR FULL SPECTRUM POLARIZATION IMAGING,” filed March 18, 2025. The entire contents of the above noted provisional application are incorporated by reference as part of the disclosure of this document.TECHNICAL FIELD

[0002] The technology described in this patent document relates to imaging methods and systems, and particularly those that are based on polarization.BACKGROUND

[0003] Full spectrum photography or imaging is a type of multispectral imaging that measures the entire spectrum of the film or the wavelength range of the camera sensor. In contrast to hyperspectral imaging where light is separated and collected in multiple narrow spectral bands, full spectrum imaging is inherently broadband and collects all the light of different wavelengths. One advantage is the high signal-to-noise ratio which is useful for night-time operation. Another advantage is the identification and discrimination of an object that is invisible to the human eyes. It is therefore important to provide improved imaging systems that cover a wide range of the spectrum.SUMMARY

[0004] The disclosed embodiments relate to methods and systems that, among other features and benefits, combine full spectrum and polarization imaging, which can provide valuable polarization information over a wide spectral range. Applications of the disclosed technology include material characterization, environmental monitoring, surveillance, remote sensing, metrology, astronomy and medical diagnosis, and others.

[0005] One example full-spectrum imaging and polarization system includes one or more pixeled sensors, where each pixelated sensor is responsive to a wide spectral range of illumination in a range of at least 250 nm to 1 .1 microns. The system further includesan optical system comprising one or more imaging elements and one or more polarization elements, wherein the one or more imaging elements are positioned to receive illumination from an object of interest and to direct the received illumination to the one or more pixelated sensors, and the one or more polarization elements are positioned to receive the illumination corresponding to the object of interest and to allow illumination with two or more distinct polarizations to reach the one or more pixelated detectors. The system additionally includes a processor and a memory including instructions stored thereon, wherein the instructions upon execution by the processor configure the processor to receive information corresponding to an intensity and polarization of illumination received from the object, and determine imaging and polarization characteristics of the object based on the received information.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 illustrates the imaginary part of the refractive index of silicon and InGaAs as a function of wavelength.

[0007] FIG. 2 illustrates a division-of-focal-plane imaging polarimeter in accordance with an example embodiment.

[0008] FIG. 3 illustrates a division-of-time imaging polarimeter in accordance with an example embodiment.

[0009] FIG. 4 illustrates a division-of-aperture imaging polarimeter in accordance with an example embodiment.

[0010] FIG. 5 illustrates a division-of-amplitude imaging polarimeter in accordance with an example embodiment.

[0011] FIG. 6 illustrates a division-of-amplitude imaging polarimeter in accordance with another example embodiment.

[0012] FIG. 7A illustrates an unobstructed reflective imaging system in accordance with an example embodiment.

[0013] FIG. 7B illustrates an unobstructed reflective imaging system in accordance with another example embodiment.

[0014] FIG. 8 illustrates an all-reflective, unobstructed microscope objective in accordance with an example embodiment.DETAILED DESCRIPTION

[0015] Most conventional sensors use semiconductor material, where the long wavelength sensitivity of the sensor is limited by the bandgap energy, Eg, of the semiconductor. Light is absorbed and detected only if it has energy greater than the bandgap energy. Examples of semiconductor material in commercially available sensors are silicon, InGaAs and InSb, which have bandgap energies of approximately 1.12 eV, 0.75 eV and 0.17 eV, respectively. The bandgap energy is related to the bandgap wavelength,g, as shown in Equation (1 ).Eg(eV = 1.24 / g(jim) (1 )

[0016] Light with wavelength longer thangis generally not detected, unless the intensity is high, and there is nonlinear absorption.gfor silicon, InGaAs and InSb are 1.107, 1.653 and 7.293 microns, respectively. FIG. 1 shows the imaginary part of the refractive index or the extinction coefficient of silicon and InGaAs as a function of wavelength.gis denoted in the plots with a vertical dashed line. The extinction coefficient k is related to the absorption coefficient, a, as shown in Equation (2). a = nk / (2)

[0017] As shown in FIG. 1 , the extinction coefficient becomes small for wavelength larger thang.

[0018] The short wavelength sensitivity of the sensor is limited by surface absorption of the semiconductor. In silicon, this is limited by silicon oxide on the silicon surface which is opaque at around 0.18 micron. Thus, a conventional silicon sensor has a wavelength sensitivity that can range from about 0.18 to 1.1 microns. A full spectrum imager using a silicon sensor utilizes the full wavelength sensitivity and covers the ultraviolet (UV), visible and part of near-infrared (NIR) spectrum.

[0019] In the embodiments disclosed herein, full spectrum imaging and polarization imaging are combined. Four different example embodiments, namely, division of focal plane, division of time, division of aperture, and division of amplitude, are described to illustrate the underlying concepts. It is understood, however, that a combination andpermutation of the four different configurations can also be implemented in accordance with example embodiments.

[0020] FIG. 2 illustrates a division-of-focal-plane imaging polarimeter 200 in accordance with an example embodiment. The imaging polarimeter includes an achromatic imaging lens 201 , covering the full spectrum of the sensor 202. The sensor 202 has an array of pixels. Each pixel has an individual polarizer 203 on top, passing light of a predefined polarization state. The dimensions of the polarizer 203 is generally the same as, or is a multiple of the dimensions of, the pixel. The polarizer can be a linear, an elliptical or a circular polarizer. In one embodiment, the array of polarizers includes a periodic array of four different elliptical polarizers, as illustrated as element 203 in FIG. 2. The four elliptical polarizers can be represented as four points on the Poincare sphere 204. The four points are located at the vertices of a tetrahedron. Examples of design and fabrication process for the elliptical polarizers are described in detail in a paper by X. Tu, L. Jiang, M. Ibn-Elhaj, S. Pau, “Design, fabrication and testing of achromatic elliptical polarizer,” Optics Express 25, 10355, 2017, for the visible spectrum, and in a paper by L. Jiang, S. Miller, X. Tu, M. Smith, Y. Zou, F. Reininger, S. Pau, “Patterned achromatic elliptical polarizer for short wave infrared imaging polarimetry,” Opt. Express 30(2), 1249- 1260, 2022, for the near infrared spectrum. These papers are incorporated by reference herein. In some embodiments, the polarimeter can be a complete polarimeter which measures all four of the Stokes parameters. In other embodiments, the polarimeter can be an incomplete polarimeter which measures a subset of the four Stokes parameters (i.e. , an array of polarizers with less than four unique polarizers may be used).

[0021] In the configuration of FIG. 2, due to the arrayed set of polarizers, the full spatial resolution of the sensor is not utilized (e.g., in the example configuration of FIG. 2, the spatial resolution is reduced by half). FIG. 3 illustrates a division-of-time imaging polarimeter 300 in accordance with an example embodiment. This configuration can utilize the full spatial resolution of the sensor. The imaging polarimeter 300 includes an achromatic retarder 301 , an achromatic polarizer 302, and an achromatic imaging lens 303, covering the full spectrum of the sensor 304. The sensor 304 has an array of pixels. The polarimeter measures images of different polarization states at different times. In oneembodiment, polarizer 302 is fixed and the retarder 301 is rotating, with its rotation synchronized to the image acquisition of the sensor 304. In another embodiment, the polarizer 302 is rotating, with rotation synchronized to the image acquisition of the sensor 304, and the retarder 301 is fixed. In still another embodiment, both the retarder 301 and polarizer 302 are rotating. In yet another embodiment, the retarder 301 includes two retarders, and both retarders are rotating with different speeds. In another embodiment, the retarder 301 is missing (not present), and the polarizer 302 is rotating. While FIG. 3 illustrates the retarder and polarizer positioned before the imaging lens, in some embodiments, the retarder and polarizer are positioned in the illumination path after the imaging lens. In yet some other embodiments, one of the retarder or the polarizer may be positioned after the imaging lens, while the other one of the retarder or the polarizer may be positioned before the lens.

[0022] In the configuration of FIG. 3, the rotation of the polarizer 302 and / or the retarder 301 can be controlled via signals that are received from a processor or controller, which cause the polarizer 302 and / or the retarder 301 to rotate with the requisite synchronization and at suitable instances in time. The polarizer 302 and / or the retarder 301 can be coupled to, or positioned on, a rotational stage, motor or similar components. While FIG. 3 configuration produces high-resolution images, it requires acquisition of multiple images in a temporal sequence. Therefore, the FIG. 3 configuration may not produce optimum results for applications where, for example, the object is moving at a high speed.

[0023] FIG. 4 illustrates a division-of-aperture imaging polarimeter 400 in accordance with an example embodiment. The imaging polarimeter 400 includes an achromatic lens 401 , another achromatic lens 402, an achromatic lens array with lenslet 403 and 404, polarizers 405 and 406, and a full spectrum sensor 407. The sensor 407 has an array of pixels. Incoming light is collimated by lens 401 and 402. The light output from lens 402 is divided into two parts by lenslet 402 and lenslet 403 and is subsequently passed through two different polarizers 405 and 406 to form two images on the sensor 407. The two images represent two measurements of two different polarization states. In this way, the entire aperture is divided into two sections, each section causing the light topass through a different polarizer. In some embodiments, there are three lenslets and three different polarizers, thus forming three images on the sensor. In another embodiment, there are four lenslets and four polarizers, in a two-by-two array, thus forming four images on the sensor. It is possible to construct a polarimeter with N lenslets, in a space filling configuration, to divide the aperture into N components, where N > 2. In one example embodiment, four lenslets along with four polarizers are used (N = 4). In this way, the set of full Stokes parameters can be obtained. Increasing the number of lenslets / polarizers beyond 4 is not strictly needed, but can produce more accurate results due to an improved signal-to-noise ratio obtained, for example, via averaging over multiple measured values.

[0024] Compared to the configuration of FIG. 2, the polarizers in the FIG. 4 configuration are larger in size and can be manufactured at a cheaper cost. The FIG. 4 polarimeter also does not require rotating or moving the polarizers, which makes this configuration simpler to design and manufacture compared to the polarimeter 300 in FIG. 3.

[0025] FIG. 5 illustrates a division-of-amplitude imaging polarimeter 500 in accordance with an example embodiment. The imaging polarimeter 500 includes an achromatic imaging lens 501 , polarization beamsplitters 502, 503, and 504, and full spectrum sensors 505, 506, 507 and 508. The polarization beamsplitters 502, 503 and 504 separate the incoming light that is incident on them into two different elliptical polarization states. Examples of design and fabrication process for the polarization beamsplitter are described in detail in a paper by a paper by S. Miller, X. Tu, L. Jiang, S. Pau, “Polarizing beam splitter cube for circular and ell iptically polarized light,” Optics Express 27, 16258, 2019, which is incorporated by reference herein. The four sensors505, 506, 507 and 508 measure four images corresponding to different polarization states. In the configuration of FIG. 5, the full spatial resolutions of the four sensors 505,506, 507 and 508 are utilized, the intensity of the light that reaches the sensors is substantially preserved, and four different polarizations measured by the sensors allow all 4 Stokes parameters to be determined. In addition, the FIG. 5 polarimeter does not require any moving components. However, polarization beamsplitters and multiplesensors can be relatively expensive. This configuration also requires precise alignment of multiple sensors and optical components.

[0026] FIG. 6 illustrates a division-of-amplitude imaging polarimeter 600 in accordance with another example embodiment. The imaging polarimeter 600 includes an achromatic imaging lens 601 , non-polarization beamsplitters 602, 603, and 604, full spectrum sensors 605, 606, 607 and 608, and polarizers 609, 610, 611 and 612. The non-polarization beamsplitters 602, 603 and 604 separate the incoming light into two components of roughly equal amplitude. The polarizers 609, 610, 611 and 612 can be elliptical, circular or linear polarizers. The four sensors 605, 606, 607 and 608 measure four images corresponding to different polarization states. Compared to FIG. 6, the beamsplitters 602, 603 and 604 are non-polarizing and can thus be easier / cheaper to produce. However, the intensity / amplitude of the light that reaches the sensors is reduced, and thus the configuration of FIG. 6 may be suitable for applications where the object and / or environment is well lit. Examples of non-polarization beamsplitters include pellicle and polka dot beamsplitters.

[0027] Achromatic imaging optics are important elements in the construction of full spectrum polarization cameras. In some embodiments, where the demands for correcting chromatic aberrations are not stringent, optical systems incorporating refractive elements are adequate. However, these systems might exhibit performance reductions at the extremes of the wavelength spectrum due to residual chromatic aberrations.

[0028] For instances requiring precise correction of chromatic aberrations, a reflective optical system is preferred. Various designs of reflective imaging systems exist, including those with central obstructions like the Cassegrain telescope and the Schwarzschild microscope objective. Nevertheless, unobstructed reflective systems are often preferred for their superior light efficiency and minimal stray light. FIG. 7 illustrates two such unobstructed three-mirror imaging systems in accordance with example embodiments: system illustrated in FIG. 7A includes three non-flat mirrors and offers a compact design with a limited field of view, whereas the system illustrated in FIG. 7B, though bulkier, receives a converging input beam and provides a much wider field ofview. Notably, in FIG. 7A, incoming diverging light (e.g., aperture of an objective) is incident on the first mirror (M1 ), is reflected towards the second mirror (M2), which reflects the light in the direction of the third mirror (M3), and is reflected to, and is received by, the sensor. In FIG. 7B, incoming converging light is incident on the first mirror (M1 ), is reflected towards the second mirror (M2), which reflects the light in the direction of the third mirror (M3), and is reflected in the direction of the image plane.

[0029] FIG. 8 illustrates an all-reflective, unobstructed microscope objective that includes four mirrors and is designed for capturing high-resolution images across the full spectrum of polarization, exemplifying its suitability for high-precision applications. Notably, in FIG. 8, light from the object plane is received by mirror M4 and is directed towards the aperture after reflections from mirrors, M4, M3 M2 and M1 .

[0030] Another limitation to image quality in full spectrum imaging is polarization aberration. The main contribution comes from light reflection by a metal mirror which has a complex refractive index. The polarization aberration in the reflective optics system can be reduced by addition of broadband anti-reflective coating. In addition, a polarization aberration compensator can be included in the optical system. Examples of polarization aberration compensator are described in the PCT Publication WO 2024 / 031047, which is incorporated by reference herein.

[0031] Using the disclosed embodiments, full spectrum and polarization imaging that can span over at least the ultraviolet, visible and infrared range of wavelengths. For example, spectral imaging over the range 250 nm to 1 .7 microns can be provided, which at the same time can allow determination of all four Stokes parameters. In some example embodiments, the spectral imaging using achromatic (or nearly achromatic) refractive elements allows a full spectral imaging in the 250 nm to 1.1 microns, while in other embodiments, the use of reflective components extend the spectral imaging range to 1.7 microns and beyond. The disclosed embodiments further enable implementation of different configurations that provide various tradeoffs in terms of spatial resolution, speed of capture and analysis, cost and complexity suitable for different applications and different users.

[0032] One aspect of the disclosed embodiments relates to a full-spectrum imaging and polarization system that includes one or more pixeled sensors, where each pixelated sensor is responsive to a wide spectral range of illumination in a range of at least 250 nm to 1.1 microns. The full-spectrum imaging and polarization system further includes an optical system comprising one or more imaging elements and one or more polarization elements, wherein the one or more imaging elements are positioned to receive illumination from an object of interest and to direct the received illumination to the one or more pixelated sensors. The one or more polarization elements are positioned to receive the illumination corresponding to the object of interest and to allow illumination with two or more distinct polarizations to reach the one or more pixelated detectors. The fullspectrum imaging and polarization system also includes a processor and a memory including instructions stored thereon. The instructions upon execution by the processor configure the processor to: receive information corresponding to an intensity and polarization of illumination received from the object, and determine imaging and polarization characteristics of the object based on the received information.

[0033] In one example embodiment, the one or more imaging elements comprise one or more refractive elements, and the imaging characteristics include imaging information in a range of wavelengths between 250 nm and 1.1 microns. In another example embodiment, the one or more imaging elements consist of a plurality of reflective elements, and the imaging characteristics include imaging information in a range of wavelengths between 250 nm and 1 .7 microns. In still another example embodiment, the one or more polarization elements include an arrayed set of polarizers that are positioned on top of the one or more sensors, each set of polarizers includes two or more polarizers, and each polarizer allow light with one type of polarization corresponding to a point on a Poincare sphere to reach the one or more pixelated sensors. Further, the one or more imaging elements are positioned to direct the illumination received from the object to the one or more polarization elements. In one example embodiment, each set of polarizers consists of four polarizers.

[0034] According to another example embodiment, the one or more polarization elements include two polarization elements comprising one or more achromatic retardersor one or more achromatic polarizers positioned sequentially in an optical path that receives the illumination from the object. Further, the two polarization elements are positioned to receive the illumination corresponding to the object at full field of view of the full-spectrum imaging and polarization system, and one or both of the two polarization elements are configured to move or rotate with respect to each other in one or more steps such that, at each step, a combination of the two polarization elements allows light having a polarization state corresponding to a single point on the Poincare sphere to pass through the combination. Additionally, the instructions upon execution by the processor configure the processor to receive the information corresponding to the intensity and polarization of the illumination received from the object for each combination before an additional movement or rotation of the one or more polarization elements. In one example embodiment, the two polarization elements consist of an achromatic retarder and an achromatic polarizer. In another example embodiment, the two polarization elements consist of two achromatic retarders. In yet another example embodiment, one of the two polarization elements is non-moving. In still another example embodiment, both polarization elements are configured to move or rotate. In another example embodiment, the two polarization elements are configured to move or rotate at different speeds.

[0035] In another example embodiment, the one or more imaging elements include two achromatic lenses and an achromatic lens array comprising two or more with lenslets, wherein the achromatic lenslet array divides the incoming illumination into two or more parts. Further, the one or more polarization elements include two or more polarizers that are positioned to receive the illumination from the object after passing through the two achromatic lenses and the achromatic lenslet array, wherein each polarizer allows light having a polarization state corresponding to a single point on the Poincare sphere to pass therethrough to the one or more sensors.

[0036] In still another example embodiment, the one or more polarization elements include a first, a second and a third polarization beamsplitter, wherein the first polarization beamsplitter is positioned to receive the illumination corresponding to the object from the one or more imaging elements and to allow light having two different polarizations to reach, respectively, a first facet of the second and a first facet of the third polarizationbeamsplitter. Further, the one or more pixelated sensors include four pixelated sensors, a first of the four pixelated sensors is positioned to receive light that exits a second facet of the second polarization beamsplitter, a second of the four pixelated sensors is positioned to receive light that exits a third facet of the second polarization beamsplitter, a third of the four pixelated sensors is positioned to receive light that exits a second facet of the third polarization beamsplitter, and a fourth of the four pixelated sensors is positioned to receive light that exits a third facet of the third polarization beamsplitter.

[0037] In yet another example embodiment, the one or more imaging elements include a first, a second and a third non-polarization beamsplitter, wherein each non-polarization beam splitter is configured to split an amplitude of illumination received thereon, the first non-polarization beamsplitter is positioned to receive the illumination corresponding to the object from the one or more imaging elements and to allow light having a lower amplitude to reach, respectively, a first facet of the second and a first facet of the third polarization beamsplitter. Further, the one or more polarization elements include four polarizers positioned on output facets of the second and the third non-polarizing beamsplitters, and the one or more pixelated sensors include four pixelated sensors, wherein a first of the four pixelated sensors is positioned to receive light that exits a second facet of the second non-polarization beamsplitter and passes through a first polarizer, a second of the four pixelated sensors is positioned to receive light that exits a third facet of the second non-polarization beamsplitter and passes through a second polarizer, a third of the four pixelated sensors is positioned to receive light that exits a second facet of the third non-polarization beamsplitter and passes through a third polarizer, and a fourth of the four pixelated sensors is positioned to receive light that exits a third facet of the third non-polarization beamsplitter and passes through a fourth polarizer. In one example embodiment, each non-polarizing beamsplitter is a 50-50 beam splitter. In still another example embodiment, each polarizer is configured to allow light having a polarization state corresponding to a single point on the Poincare sphere to pass therethrough to a corresponding pixelated sensor.

[0038] In another example embodiment, the plurality of reflective elements includes three non-flat mirrors. In still another example embodiment, the plurality of reflectiveelements is configured to expand a size of an input beam that is received by the reflective elements. In yet another example embodiment, the plurality of reflective elements is configured to receive a converging input beam that is received by the reflective elements. In another example embodiment, the plurality of reflective elements includes four non-flat mirrors positioned in an unobstructed microscope objective configuration.

[0039] Various components may be controlled, or various operations may be performed via implementations using a processor / controller that is configured to include, or be coupled to, a memory that stores processor executable code that causes the processor / controller carry out various computations and processing of information. The processor / controller can further generate and transmit / receive suitable information to / from the various system components, as well as suitable input / output (IO) capabilities (e.g., wired or wireless) to transmit and receive commands and / or data. The processor / controller may, for example, provide signals to control the operation of various components such as light sources and detectors that are disclosed herein.

[0040] Various information and data processing operations described herein may be implemented in one embodiment by a computer program product, embodied in a computer-readable medium, including computer-executable instructions, such as program code, executed by computers in networked environments. A computer-readable medium may include removable and non-removable storage devices including, but not limited to, Read Only Memory (ROM), Random Access Memory (RAM), compact discs (CDs), digital versatile discs (DVD), cloud storage, etc. Therefore, the computer-readable media that is described in the present application comprises non-transitory storage media. Generally, program modules may include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Computer-executable instructions, associated data structures, and program modules represent examples of program code for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represents examples of corresponding acts for implementing the functions described in such steps or processes.

[0041] Only a few implementations and examples are described and otherimplementations, enhancements and variations can be made based on what is described and illustrated in this patent document.

Claims

CLAIMSWhat Is Claimed Is:

1. A full-spectrum imaging and polarization system, comprising: one or more pixeled sensors, each pixelated sensor responsive to a wide spectral range of illumination in a range of at least 250 nm to 1.1 microns; an optical system comprising one or more imaging elements and one or more polarization elements, wherein the one or more imaging elements are positioned to receive illumination from an object of interest and to direct the received illumination to the one or more pixelated sensors, the one or more polarization elements are positioned to receive the illumination corresponding to the object of interest and to allow illumination with two or more distinct polarizations to reach the one or more pixelated detectors; and a processor and a memory including instructions stored thereon, wherein the instructions upon execution by the processor configure the processor to: receive information corresponding to an intensity and polarization of illumination received from the object, and determine imaging and polarization characteristics of the object based on the received information.

2. The full-spectrum imaging and polarization system of claim 1 , wherein the one or more imaging elements comprise one or more refractive elements, and the imaging characteristics include imaging information in a range of wavelengths between 250 nm and 1.1 microns.

3. The full-spectrum imaging and polarization system of claim 1 , wherein the one or more imaging elements consist of a plurality of reflective elements, and the imaging characteristics include imaging information in a range of wavelengths between 250 nmand 1.7 microns.

4. The full-spectrum imaging and polarization system of claim 1 , wherein: the one or more polarization elements include an arrayed set of polarizers that are positioned on top of the one or more sensors, each set of polarizers includes two or more polarizers, each polarizer allows light with one type of polarization corresponding to a point on a Poincare sphere to reach the one or more pixelated sensors; and the one or more imaging elements are positoned to direct the illumination received from the object to the one or more polarization elements.

5. The full-spectrum imaging and polarization system of claim 4, wherein each set of polarizers consists of four polarizers.

6. The full-spectrum imaging and polarization system of claim 1 , wherein: the one or more polarization elements include two polarization elements comprising one or more achromatic retarders or one or more achromatic polarizers positioned sequentially in an optical path that receives the illumination from the object, the two polarization elements are positioned to receive the illumination corresponding to the object at full field of view of the full-spectrum imaging and polarization system, one or both of the two polarization elements are configured to move or rotate with respect to each other in one or more steps such that, at each step, a combination of the two polarization elements allows light having a polarization state corresponding to a single point on the Poincare sphere to pass through the combination, and the instructions upon execution by the processor configure the processor to receive the information corresponding to the intensity and polarization of the illumination received from the object for each combination before an additional movement or rotation of the one or more polarization elements.

7. The full-spectrum imaging and polarization system of claim 6, wherein the twopolarization elements consist of an achromatic retarder and an achromatic polarizer.

8. The full-spectrum imaging and polarization system of claim 6, wherein the two polarization elements consist of two achromatic retarders.

9. The full-spectrum imaging and polarization system of claim 6, wherein one of the two polarization elements is non-moving.

10. The full-spectrum imaging and polarization system of claim 6, wherein both polarization elements are configured to move or rotate.

11. The full-spectrum imaging and polarization system of claim 6, wherein the two polarization elements are configured to move or rotate at different speeds.

12. The full-spectrum imaging and polarization system of claim 1 , wherein the one or more imaging elements include two achromatic lenses and an achromatic lens array comprising two or more with lenslets, wherein the achromatic lenslet array divides the incoming illumination into two or more parts; and wherein the one or more polarization elements include two or more polarizers that are positioned to receive the illumination from the object after passing through the two achromatic lenses and the achromatic lenslet array, each polarizer allowing light having a polarization state corresponding to a single point on the Poincare sphere to pass therethrough to the one or more sensors.

13. The full-spectrum imaging and polarization system of claim 1 , wherein: the one or more polarization elements include a first, a second and a third polarization beamsplitter, the first polarization beamsplitter positioned to receive the illumination corresponding to the object from the one or more imaging elements and to allow light having two different polarizations to reach, respectively, a first facet of the second and a first facet of the third polarization beamsplitter,the one or more pixelated sensors including four pixelated sensors, wherein: a first of the four pixelated sensors is positioned to receive light that exits a second facet of the second polarization beamsplitter, a second of the four pixelated sensors is positioned to receive light that exits a third facet of the second polarization beamsplitter, a third of the four pixelated sensors is positioned to receive light that exits a second facet of the third polarization beamsplitter, and a fourth of the four pixelated sensors is positioned to receive light that exits a third facet of the third polarization beamsplitter.

14. The full-spectrum imaging and polarization system of claim 1 , wherein: the one or more imaging elements include a first, a second and a third nonpolarization beamsplitter, each non-polarization beam splitter configured to split an amplitude of illumination received thereon, the first non-polarization beamsplitter positioned to receive the illumination corresponding to the object from the one or more imaging elements and to allow light having a lower amplitude to reach, respectively, a first facet of the second and a first facet of the third polarization beamsplitter, the one or more polarization elements include four polarizers positioned on output facets of the second and the third non-polarizing beamsplitters, the one or more pixelated sensors including four pixelated sensors, wherein: a first of the four pixelated sensors is positioned to receive light that exits a second facet of the second non-polarization beamsplitter and passes through a first polarizer, a second of the four pixelated sensors is positioned to receive light that exits a third facet of the second non-polarization beamsplitter and passes through a second polarizer, a third of the four pixelated sensors is positioned to receive light that exits a second facet of the third non-polarization beamsplitter and passes through a third polarizer, and a fourth of the four pixelated sensors is positioned to receive light that exitsa third facet of the third non-polarization beamsplitter and passes through a fourth polarizer.

15. The full-spectrum imaging and polarization system of claim 14, wherein each nonpolarizing beamsplitter is a 50-50 beam splitter.

16. The full-spectrum imaging and polarization system of claim 14, wherein each polarizer is configured to allow light having a polarization state corresponding to a single point on the Poincare sphere to pass therethrough to a corresponding pixelated sensor.

17. The full-spectrum imaging and polarization system of claim 3, wherein the plurality of reflective elements includes three non-flat mirrors.

18. The full-spectrum imaging and polarization system of claim 17, wherein the plurality of reflective elements is configured to expand a size of an input beam that is received by the reflective elements.

19. The full-spectrum imaging and polarization system of claim 17, wherein the plurality of reflective elements is configured to receive a converging input beam that is received by the reflective elements.

20. The full-spectrum imaging and polarization system of claim 3, wherein the plurality of reflective elements includes four non-flat mirrors positioned in an unobstructed microscope objective configuration.

Images